GNU Info

(as.info)Macro

---

Next: MRI Prev: Long Up: Pseudo Ops

---

Enter node , (file) or (file)node

`.macro'
========

   The commands `.macro' and `.endm' allow you to define macros that
generate assembly output.  For example, this definition specifies a
macro `sum' that puts a sequence of numbers into memory:

             .macro  sum from=0, to=5
             .long   \from
             .if     \to-\from
             sum     "(\from+1)",\to
             .endif
             .endm

With that definition, `SUM 0,5' is equivalent to this assembly input:

             .long   0
             .long   1
             .long   2
             .long   3
             .long   4
             .long   5

`.macro MACNAME'
`.macro MACNAME MACARGS ...'
     Begin the definition of a macro called MACNAME.  If your macro
     definition requires arguments, specify their names after the macro
     name, separated by commas or spaces.  You can supply a default
     value for any macro argument by following the name with `=DEFLT'.
     For example, these are all valid `.macro' statements:

    `.macro comm'
          Begin the definition of a macro called `comm', which takes no
          arguments.

    `.macro plus1 p, p1'
    `.macro plus1 p p1'
          Either statement begins the definition of a macro called
          `plus1', which takes two arguments; within the macro
          definition, write `\p' or `\p1' to evaluate the arguments.

    `.macro reserve_str p1=0 p2'
          Begin the definition of a macro called `reserve_str', with two
          arguments.  The first argument has a default value, but not
          the second.  After the definition is complete, you can call
          the macro either as `reserve_str A,B' (with `\p1' evaluating
          to A and `\p2' evaluating to B), or as `reserve_str ,B' (with
          `\p1' evaluating as the default, in this case `0', and `\p2'
          evaluating to B).

     When you call a macro, you can specify the argument values either
     by position, or by keyword.  For example, `sum 9,17' is equivalent
     to `sum to=17, from=9'.

`.endm'
     Mark the end of a macro definition.

`.exitm'
     Exit early from the current macro definition.

`\@'
     `as' maintains a counter of how many macros it has executed in
     this pseudo-variable; you can copy that number to your output with
     `\@', but _only within a macro definition_.